After the conclusion of the Rise of the Red Shadows storyline, I was thinking that Mars Herring and Red Shadow confederates made off with Serpentor before blowing up the facility the Jugglers had him stashed in. Wilder and his compatriots never seemed to be the type to let something as valuable as him go to waste. And since the original Black Major's origin revolved around him being brainwashed to work for Ironblood and company, it seems fitting for Serpentor II to take the role. Also seeing that Hasbro awhile back released a Serpentor figure with black highlights, I could see him, even if and when he recoveres from the brainwashing, adding the look to his outfit.

It's Possible Black Haired Dudes tend to go grey overnight :lol :and John Shepherd is not his real name either(to protect his family name they used Shepherd in the story I'm colouring right now )..not sure the beard suits him though .